1. Field of the Invention
The present invention relates to a pedestrian protection apparatus for a vehicle, and in particular to an improved structure of the pedestrian protection apparatus disposed at a lower region of a front part of the vehicle and arranged to apply a counterforce to a leg portion of a pedestrian by contact with the leg portion of the pedestrian that has collided or contacted with a front face of the vehicle, thereby protecting the leg portion of the pedestrian.
2. Description of the Related Art
In vehicles such as automobiles, there are conventionally disposed, at a front face, a rear face, or side faces, of the vehicles, various types of protection apparatuses which absorb an impact energy generated upon a collision, for thereby protecting the vehicle body and vehicle passengers. In recent years, there is also disposed, at the front face of the vehicle, an apparatus for protecting a pedestrian upon collision (contact) of the pedestrian with the front face of the vehicle.
As one type of the pedestrian protection apparatuses, there is known an apparatus which is disposed inside of a front bumper or at a lower part of the front bumper independently of the front bumper. The apparatus is arranged to apply, to a leg portion of the pedestrian, a counterforce with respect to an impact load that is inputted upon collision of the pedestrian with the front face of the vehicle, thereby causing the pedestrian to be thrown toward a member such as a hood that can absorb the impact. Thus, it is possible to assure protection and safety of the pedestrian.
Various structures of the pedestrian protection apparatuses are conventionally proposed. For example, U.S. Pat. No. 6,893,064 discloses a pedestrian protection apparatus including a resin base member that is disposed in a lower region of a front part of a vehicle so as to extend in a front to back direction of the vehicle and fixed to the vehicle at a rear portion thereof and a plurality of reinforcing beads that is integrally formed at a plurality of positions spaced apart from each other in a vehicle width direction at a front portion of the base member so as to extend in a front to back direction of the vehicle. The reinforcing beads have an angular U-shape in cross section protruding at least one of upward and downward. The apparatus is configured to apply a counterforce to a leg portion of a pedestrian that has collided with the front of the vehicle by contact of a front end part of the base member with the leg portion of the pedestrian, thereby protecting the pedestrian.
The pedestrian protection apparatus having such a structure can achieve sufficient weight reduction and excellent moldability because it is formed of an integrally-molded resin product. Further, while keeping the height of the reinforcing beads relatively small, the front portion of the base member can have substantially the same rigidity as the rigidity that would be achieved, for example, when a high planar rib is integrally formed. Therefore, desired pedestrian protection performance can be advantageously exhibited with a compact structure.
However, the inventors of the present invention studied the conventional pedestrian protection apparatuses equipped with reinforcing beads from various aspects and found that, because such a pedestrian protection apparatus is formed of an integrally-molded resin product including the base member and the plurality of reinforcing beads, the entire apparatus sometimes suffer from bending deformation (warping deformation) due to thermal contraction occurring inevitably after the molding of such an integrally-molded product.
That is, in the conventional pedestrian protection apparatuses equipped with reinforcing beads, generally, the base member extending in the vehicle width direction has a front end surface with a convex curved configuration protruding to the front of the vehicle. However, the thermal contraction after the molding sometime causes a phenomenon in which the entire apparatus bends (warps) such that the radius of curvature of the front end surface of the base member is increased. If this happens, it not only makes installation of the base member to the lower region of the front face of the vehicle difficult, but also may deteriorate the pedestrian protection performance, depending on the deformed condition.